Users who are troubleshooting scenarios where the AppDynamics Standalone Machine Agent is not reporting metrics as expected will find causes and solutions here.The following solutions apply to versions 4.4 and higher.
If both an App Server Agent and the Machine Agent are unzipped into the same directory, important files will be overwritten, such as thelog4j.xmlfile.
When unzipping the App Agent or Machine Agent zip files, make sure to use different directories.
Problem: Host ID for App Server Agent and Machine Agent do not match
Both the App Server Agent and the Machine Agent use the Java API to get the host ID.The results from the API can be inconsistent and the same JVM can sometimes return a different value for the same machine each time the Machine Agent is restarted.
When the host ID is then registered with the Controller the app server agent and the machine agent can be assigned different host IDs even though they are running on the same machine.
Reset the hostname for the Machine Agent by running the agent with the
-Dappdynamics.agent.uniqueHostIdJVM parameter. Set the host ID to be the same as the one the App Server Agent is using.
Problem: Difficulty with machine hostname resolution
If the following error is seen in the Machine Agent log file, the cause is hostname resolution, which affects Machine Agent startup and registration.
.ERROR XMLConfigManager - Error in Default Host Identifier Resolver resolving host name java.net.UnknownHostException: log-aggregate01: log-aggregate01